Equipment rooms at facilities such as telecommunications central offices and computer data centers and the like house electronic systems, electro-optical systems, photonic systems, computing systems and the like (generally speaking, equipment). The equipment is installed in racks within cabinets arranged in rows separated by aisles over a raised floor in an equipment room. Cold air exits the raised floor from “cold aisles” and is pulled through the cabinets by fans. The air egresses the cabinets in the “hot aisles” where it is pulled by room-level air blowers through a centrally located heat exchanger. The heat exchanger cools the air down and returns it to a compartment beneath the cold aisles of the raised floor of the equipment room.
Various modifications to the hot/cold aisles configuration are known. For example, one modification uses a fluid cooled heat exchanger to insure that air exiting from the cabinet is cooled to some extent before entering the equipment room hot aisle. The main purpose of this approach is to prevent heated air from the “hot aisle” inadvertently entering another cabinet from the front due to limited equipment room airflow control. Flow-balancing problems can create hot-spots within the equipment room as well. As the temperature of the air entering the raised floor is lowered, the cooling burden on the equipment room HVAC system is increased; however the air is not necessarily cooled to a sufficiently low level for use by the equipment shelves in the cabinets due to limited air flow distribution efficiency. It is also known to use refrigerant pumped loops with external chillers to augment a standard system. These units can be mounted in the ceiling above the cabinet, or directly on the cabinet, directing cool air towards the shelf intake vents. In addition, complex plumbing may be used to provide cooling fluids to individual circuit packs or circuit pack components.